WHAT IS THE PSA (PROSTATE SPECIFIC ANTIGEN) TEST?

Prostate-specific antigen (PSA) is a protein produced by cells of the prostate gland, a small gland about the size and shape of a walnut that sits below a man’s bladder. Small amounts of PSA ordinarily circulate in the blood. The PSA test measures the level of PSA in the blood.

The PSA test is a blood test used primarily to screen for prostate cancer before symptoms appear. Because PSA is produced by the body and can be used to detect disease, it is sometimes called a biological marker or a tumor marker.

It is normal for men to have a low level of PSA in their blood; however, prostate cancer or benign (not cancerous) conditions can increase a man’s PSA level. As men age, both benign prostate conditions and prostate cancer become more common. The most frequent benign prostate conditions are prostatitis (inflammation of the prostate) and benign prostatic hyperplasia, BPH enlargement of the prostate. There is no evidence that prostatitis or BPH causes cancer, but it is possible for a man to have one or both of these conditions and to develop prostate cancer as well.

A man’s PSA level alone does not give doctors enough information to distinguish between benign prostate conditions and cancer. However, the doctor will take the result of the PSA test into account when deciding whether to check for further signs of prostate cancer.

Several risk factors increase a man’s chances of developing prostate cancer. These factors may be taken into consideration when a doctor recommends screening.

Age is the most common risk factor, with nearly 63 percent of prostate cancer cases occurring in men age 65 and older.

Family history – Men who have a father or brother with prostate cancer have a greater chance of developing prostate cancer.

Race – African American men have the highest rate of prostate cancer, while Asian and Native American men have the lowest rates.

Possibly diet – There is some evidence that a diet higher in fat, especially animal fat, may increase the risk of prostate cancer.

In general, the higher a man’s PSA level, the more likely it is that cancer is present. Furthermore, if a man’s PSA level continues to rise over time, other tests may be needed.